#### Answer

$\displaystyle \frac{3}{16}$ of herd left to vaccinate

#### Work Step by Step

To find the fraction left to vaccinate, we subtract the amount vaccinated ($3/16$ and $1/4$) from the amount need to be vaccinated ($5/8$):
$\displaystyle \frac{5}{8}-\frac{3}{16}-\frac{1}{4}=$
We find the Least Common Denominator, which is 16:
$=\displaystyle \frac{5*2}{8*2}-\frac{3}{16}-\frac{1*4}{4*4}$
$=\displaystyle \frac{5*2}{16}-\frac{3}{16}-\frac{1*4}{16}$
$=\displaystyle \frac{10}{16}-\frac{3}{16}-\frac{4}{16}$
$=\displaystyle \frac{10-3-4}{16}$
$=\displaystyle \frac{3}{16}$ of herd left to vaccinate